body {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    background: #2c3e50;
    font-family: Arial, sans-serif;
    overflow: hidden;
}

.card-container {
    position: relative;
    width: 300px;
    height: 400px;
    perspective: 1800px;
    cursor: grab;
}

.card-container:active {
    cursor: grabbing;
}

.card {
    width: 100%;
    height: 100%;
    position: absolute;
    transform-style: preserve-3d;
    will-change: transform;
}

.card-face {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    border-radius: 20px;
    box-shadow: 0 15px 45px rgba(0,0,0,0.3);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 32px;
    user-select: none;
    background: linear-gradient(45deg, #000000, #000000);

    transition: box-shadow 0.2s ease-out;
}

.front{
    background-repeat: no-repeat; /* 背景图片不重复 */
    background-size: cover; /* 背景图片覆盖整个元素 */
    background-position: center; /* 背景图片居中 */

    color: #ffffff;
}

.back {
    background: linear-gradient(45deg, #ff6b6b, #ff4757);
    color: white;
    transform: rotateY(180deg);
    background-repeat: no-repeat; /* 背景图片不重复 */
    background-size: cover; /* 背景图片覆盖整个元素 */
    background-position: center; /* 背景图片居中 */
}

.particles {
    position: absolute;
    width: 100%;
    height: 100%;
    pointer-events: none;
}

.particle {
    position: absolute;
    border-radius: 50%;
    background-color: rgba(254, 255, 147, 0.7);
    opacity: 0;
    will-change: transform;
}

/* 现代风格 */
a.modern-style {
    position: relative;
    display: inline-block;
    padding: 10px 20px;
    color: #ff4757;
    background-color: #ff6b6b;
    text-decoration: none;
    border-radius: 5px;
    overflow: hidden;
    transition: background-color 0.3s ease;
}

/* 现代风格鼠标悬停效果 */
a.modern-style:hover {
    background-color: #b10000;
}

/* 现代风格的下划线动画 */
a.modern-style::after {
    content: '';
    position: absolute;
    width: 100%;
    transform: scaleX(0);
    height: 2px;
    bottom: 0;
    left: 0;
    background-color: #fff;
    transform-origin: bottom right;
    transition: transform 0.25s ease-out;
}

a.modern-style:hover::after {
    transform: scaleX(1);
    transform-origin: bottom left;
}